1. Field of the Invention
The present invention generally relates to a detection apparatus and particularly an apparatus adapted for the detection of seed germination. The present invention particularly utilizes a light beam at a work station for the detection.
2. Prior Art
U.S. Pat. Nos. 3,852,914 to Levengood and 4,230,983 to Steere describe seed viability detectors. These patents describe apparatus which use electrical conductivity of wet seeds or solutions with seeds to determine viability. These detectors require time consuming and careful set up and are affected by contamination. The results only correlate with the actual germination percentage of a given seed lot which in conventional practice is determined by direct observation and manual counting of imbibed seeds under controlled growing conditions. Christ, R. A., J. of Exp. Botany, Vol 29, No. 110, pages 603-610 (June 1978) describes a method whereby the elongation rate of leaves is measured directly by a counterweight used for the measurement which would not be useful for seed germination.
Various prior art references describe the measurement of root length using an estimating method based upon the intersection of a series of parallel lines overlapping the roots. One instrument uses a photoelectric detection device which scans a surface on which a root sample is placed using a parallel line pattern. Root interference reduces light intensity to the detection device thus indicating the presence of a root and can be used to calculate root length. References which describe this method are:
Newman, E. I., J. Appl. Ecol. 3:139-145 (1966) PA1 Rowse, H. R. et al., J. Appl. Ecol. 11:309-314 (1974) PA1 Richards, D. et al., Plant and Soil 52:69-76 (1979) PA1 Goubran, F. H. et al., Plant and Soil 52:77-83 (1979) PA1 Voorhees, W. B. et al., Agronomy Journal 72:847-851 (1980)
The method not be useful for the detection of seed germination because of interference of the seeds with the light.